The aims of this project are to investigate the clinical, ophthalmologic, hematologic, epidemiologic, biochemical, and molecular features of genetic defects of human pigment formation, particularly oculocutaneous albinism. These studies will provide information which we hope will lead to methods of accurate diagnosis, therapy, and family counseling, so that these genetic diseases can be prevented, treated, or ameliorated. Clinical and epidemiologic studies of albinism and the Hermansky-Pudlak syndrome will be carried out in Puerto Rico. The natural history of the disease will be elucidated, including the pigmentary and ocular changes, and the morbidity and mortality which results from the storage of ceroid-like material in the kidneys, lungs, heart, and gastrointestinal tract. The defects in the regulatory mechanisms and membranes in platelets and blood cells in Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, and other inherited pigment disorders will be investigated. The relationship between the storage pool deficiency and the hypopigmentation will be analyzed. Biochemical and molecular studies will provide methods for accurate diagnosis and insight into mechanisms of albinism. Dopachrome oxidoreductase will be purified and characterized, and the role of this enzyme in the regulation of pigment will be analyzed. The tyrosinase gene will be isolated and normal and mutant genes will be characterized. Visual function studies in albinism will be carried out and methods of visual and educational intervention analyzed. The role of thioredoxin reductase in oxygen radical defense in vitiligo will be determined.